In the production of dentures and appliances such as occusal splints, it is necessary to provide for occlusal free space between the maxillary and mandibular arches. The free space occurs when a patient's jaws are unclenched and occupy a relaxed or at rest position in which the upper and lower teeth are vertically spaced from one another. The extent of the spacing or free space between the teeth is difficult to ascertain due to the inability of the dentist to obtain accurate measurements within the patient's mouth.
The problems associated with determining the occlusal free space when a patient's jaws are in a relaxed condition has been recognized heretofore and many proposals have been advanced for overcoming or minimizing such problems. However, not all of the proposals have been satisfactory for a variety of reasons, such as complexity, difficulty in use, and causing apprehension on the part of the patient.
An object of this invention is to provide an instrument for accurately determining the normal free space between a patient's upper and lower jaws and which overcomes the objectionable characteristics of previously proposed apparatus for similar purposes.